A new report on 2 patients with hereditary angioedema (HAE) with normal C1-inhibitor (C1-INH) and factor XII mutation (nC1-FXII) found that the administration of lanadelumab, a human immunoglobulin recombinant monoclonal antibody, was effective in preventing attacks. The report, published in the Annals of Allergy, Asthma & Immunology, suggests that larger studies on this medication are warranted.

“Lanadelumab efficacy and safety have only been reported in HAE with C1-INH deficiency so far,” the authors wrote. “We present for the first time data on lanadelumab effectiveness in the prevention of HAE attacks in 2 patients with HAEnC1-FXII.”

Current treatment alternatives for patients with HAEnC1 include C1-INH concentrates, progestins, and tranexamic acid, but in some patients, such as those in this report, these therapies are not effective and are poorly tolerated.

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The first patient in this report was a 42-year-old woman who was receiving long-term prophylaxis with tranexamic acid, progestin, and an injectable C1-INH concentrate, but had still had 7 attacks in the previous 6 months, 2 of which were severe. After starting 300 mg of subcutaneous lanadelumab twice monthly, her attacks reduced markedly from 1.17 per month to 0.32 per month. She experienced chronic urticaria as an adverse event, which was treated with antihistamines.

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The other patient was a 48-year-old woman who was treated with intravenous C1-INH during her pregnancies and tranexamic acid and progestin for 20 years. She still had an abdominal attack every 2 months and ultimately had to withdraw from progestin and tranexamic acid due to adverse effects, which led to 2 attacks per month. Treatment with 300 mg of subcutaneous lanadelumab twice monthly led to 5 months without a single attack. No adverse events had been reported.

Both patients are still currently on lanadelumab. Due to these patients’ results and the convenient subcutaneous administration of lanadelumab, the authors recommend further studies on a larger sample of patients with HAEnC1-FXII.


Bouillet L, Bocquet A, Belbezier A, Boccon-Gibod I. Effectiveness of lanadelumab in patients with hereditary angioedema with normal C1 inhibitor and FXII mutation. Ann Allergy Asthma Immunol. 2021;127(3):391-392. doi:10.1016/j.anai.2021.05.028